Highly compressible paracetamol - II. Compression properties.

Paracetamol particles crystallized in the presence of polyvinylpyrrolidone (PVP) exhibited an obvious improvement in their compression properties compared to untreated paracetamol. Paracetamol particles crystallized in the presence of 0.5% w/v PVP 10000 or PVP 50000 produced tablets with improved crushing strength with no tendency to cap even at high compression speeds. The very low values of strain rate sensitivity (SRS) and the lack of reduction in crushing strength with increasing compression speed for these particles, were indicative of a high degree of fragmentation during compression. The results of elastic recoveries and elastic energies of tablets were indicative of much less elastic behaviour of these particles than untreated paracetamol. The low elastic energy/plastic energy (EE/PE) ratio for paracetamol crystallized in the presence of PVP indicated that, contrary to untreated paracetamol, a minor portion of compression energy was utilized as elastic energy.